redhat/Makefile: remove defunct Makefile.common
Bugzilla: INTERNAL
Upstream Status: RHEL-only
Remove redhat/Makefile.common entirely.
The file was left behind, but is no longer used since:
3ec4e2a4 ("redhat: Combine Makefile and Makefile.common")
Signed-off-by: Eric Chanudet echanude@redhat.com